A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube construction techniques rather than traditional tunnel boring methods.
A slurry wall is a civil engineering technique used to build reinforced concrete walls in areas of soft earth close to open water, or with a high groundwater table. This technique is typically used to build diaphragm (water-blocking) walls surrounding tunnels and open cuts, and to lay foundations.
A tunnelling shield is a protective structure used during the excavation of large, man-made tunnels. When excavating through ground that is soft, liquid, or otherwise unstable, there is a potential health and safety hazard to workers and the project itself from falling materials or a cave-in. A tunnelling shield can be used as a temporary support structure. It is usually in place for the short-term from when the tunnel section is excavated until it can be lined with a permanent support structure. The permanent structure may be made up of, depending on the period, bricks, concrete, cast iron, or steel. Although modern shields are commonly cylindrical, the first "shield", designed by Marc Isambard Brunel, was actually a large, rectangular, scaffold-like iron structure with three levels and twelve sections per level, with a solid load-bearing top surface. The structure protected the men from cave-ins as they laboured within it, digging the tunnel out in front of the shield.
A tunnel boring machine (TBM), also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They may also be used for microtunneling. They can be designed to bore through hard rock, wet or dry soil, or sand. Tunnel diameters can range from one metre (3.3 ft) (micro-TBMs) to 17.6 metres (58 ft) to date. Tunnels of less than a metre or so in diameter are typically done using trenchless construction methods or horizontal directional drilling rather than TBMs. TBMs can be designed to excavate non-circular tunnels, including u-shaped, horseshoe, square or rectangular tunnels.
Drilling and blasting is the controlled use of explosives and other methods such as gas pressure blasting pyrotechnics, to break rock for excavation. It is practiced most often in mining, quarrying and civil engineering such as dam, tunnel or road construction. The result of rock blasting is often known as a rock cut.
The Stormwater Management And Road Tunnel, E38, is a storm drainage and road structure in Kuala Lumpur, Malaysia, and a major national project in the country. The 9.7 km (6.0 mi) tunnel is the longest stormwater drainage tunnel in Southeast Asia and second longest in Asia.
Gamuda Berhad is an engineering, property and infrastructure company based Malaysia. It is one of the largest Malaysian infrastructure companies and has undertaken various projects, both locally and overseas, like the construction of Klang Valley MRT lines, highways, airport runways, railways, tunnels, water treatment plants, dams, infrastructure concessions and the development of new townships.
Metro Tunneling Group or MTG is a Joint Venture (JV) of 5 companies currently working as the main contractor for the Delhi Metro Rail Corporation (DMRC). The 5 companies are DYWIDAG Systems from Germany, Larsen & Toubro from India, Samsung Corporation from South Korea, Ircon International from India, and Shimizu Corporation from Japan. DMRC is the joint venture of Government of India and Government of Delhi.
Herrenknecht AG is a German company that manufactures tunnel boring machines, headquartered in Allmannsweier, Schwanau, Baden-Württemberg. It is the worldwide market leader for heavy tunnel boring machines. Roughly two-thirds of its 5,000 employees work at the company's headquarters in the installation of hydraulic and electronic components and final inspection. Approximately 300 work at three locations across China. The company has 82 subsidiaries around the world and has worked on 2,600 projects.
The M5 Legacy Way is a 4.6 kilometres (2.9 mi) long tunnel linking the Western Freeway at Toowong and the Inner City Bypass at Kelvin Grove, Brisbane. The project consisted of two bored tunnels carrying two motorway grade lanes of traffic in each direction. It opened on 25 June 2015 and is the fourth of five components of Brisbane City Council's TransApex Project. The tunnels will be tolled for approximately 45 years.
The Inland Feeder is a 44 mi (71 km) high capacity water conveyance system that connects the California State Water Project to the Colorado River Aqueduct and Diamond Valley Lake. The Metropolitan Water District of Southern California designed the system to increase Southern California's water supply reliability in the face of future weather pattern uncertainties, while minimizing the impact on the San Francisco Bay/Sacramento–San Joaquin River Delta environment in Northern California. The feeder takes advantage of large volumes of water when available from Northern California, depositing it in surface storage reservoirs, such as Diamond Valley Lake, and local groundwater basins for use during dry periods and emergencies. This improves the quality of Southern California drinking water by allowing more uniform blending of better quality water from the state project with Colorado River supplies, which has a higher mineral content.
John Vernon Bartlett was a British civil engineer, particularly associated with developments in tunnelling technologies. He was President of the Institution of Civil Engineers from November 1982 to November 1983, and received various industry honours including the Telford and Sir Frank Whittle Medals.
The Eurasia Tunnel is a road tunnel in Istanbul, Turkey, crossing underneath the Bosphorus strait. The tunnel was officially opened on 20 December 2016 and opened to traffic on 22 December 2016.
A station box is a term in the construction industry: It describes a box-like underground structure for a transportation system, for example a metro or tube station.
The Bözberg Rail Tunnel is a railway tunnel in the Swiss canton of Aargau. It takes the Bözberg railway line of the Swiss Federal Railways under the Bözberg Pass between Effingen and Schinznach-Dorf. The original tunnel was opened during 1875; it is set to be closed to rail traffic during 2020-2021 following the commissioning of its replacement, after which it shall be converted and retained for service and rescue purposes in respect to its successor.
The Waterview Tunnel is a twin road tunnel in central Auckland, New Zealand. At 2,400 metres (7,900 ft) long, it is New Zealand's longest road tunnel. The tunnel, with three lanes of road vehicle traffic in each direction, connects State Highway 20 in the south at Mount Roskill to State Highway 16 in the west at Point Chevalier as part of the Waterview Connection. Its opening completed the Western Ring Route motorway system.
Tunnels are dug in types of materials varying from soft clay to hard rock. The method of tunnel construction depends on such factors as the ground conditions, the ground water conditions, the length and diameter of the tunnel drive, the depth of the tunnel, the logistics of supporting the tunnel excavation, the final use and shape of the tunnel and appropriate risk management. Tunnel construction is a subset of underground construction.
Tunnel rock recycling is a method to process rock debris from tunneling into other usable needs. The most common is for concrete aggregates or as subbase for road building. Crushers and screeners normally used in quarries are stationed at the tunnel site for the purpose which is to crush and screen the rock debris for further use. The largest tunnel rock recycling facility ever to be created was for the construction of the Gotthard Base Tunnel which took 17 years, finishing in 2016. 1/5 of the rock debris excavated for the tunnel was recycled and used as aggregates for the concrete lining inside the tunnel.
The Chiltern Tunnel is a high-speed railway tunnel currently under construction in Buckinghamshire and Hertfordshire, England, and will upon completion carry the High Speed 2 (HS2) railway line under the Chiltern Hills. The twin-bore tunnels, which are 16.04 km long, will be the longest on the HS2 line.
Euston tunnel is a tunnel currently planned in London that will carry the High Speed 2 (HS2) railway between Euston railway station and Old Oak Common railway station.
